Ion implantation is a standard technique for introducing conductivity-altering impurities into semiconductor substrates. A desired impurity material is ionized in an ion source, the ions are accelerated to form an ion beam of prescribed energy, and the ion beam is directed at the surface of the substrate. The energetic ions in the beam penetrate into the bulk of the semiconductor material and are embedded into the crystalline lattice of the semiconductor material to form a region of desired conductivity.
Solar cells are only one example of a device that uses silicon substrates, but these solar cells are becoming more important globally. Any reduced cost to the manufacturing or production of high-performance solar cells or any efficiency improvement to high-performance solar cells would have a positive impact on the implementation of solar cells worldwide. This will enable the wider availability of this clean energy technology.
Solar cell efficiency may be improved by, for example, doping the regions under metal lines more than between lines as this reduces contact resistance. This can be done with masks, which may either move with the wafer, or be fixed. The first may reduce throughput significantly or increase complexity, so the latter may be preferable. However, one issue associated with the use of fixed masks is the ability to insure and measure the alignment of the mask with the workpiece. Often, alignment verification techniques are cumbersome and time consuming. Therefore, it would be beneficial if there were a system and method to reduce the time required to insure alignment of masks, particularly for use in the creation of solar cells.